If you walked into Nazareth Barbell and said "i want to powerlift" we would have you dragging and doing other GPP movements 6 days a week. The last thing we would have you do is worry about bulking up because your coefficient is already very low. It seems that you lack the base or core strength and that would be remedied before any concerns about your BW.
My point is not that you should get leaner ( but that would be one of the results of diligent GPP work) , rather that gaining more adipose tissue (the bulk of your weight gain) will be of no benfit. A 6X day balanced meal plan very low in simple carbs totalling maybe a 200-300 Kcal in surplus would be far better.
If an experienced class 1 or 2 powerlifter said " I want to move up a weight class" my response would be very different. With 4 months in you willl hit Prs consistantly w/o significant weight gain. On a PL based program you are doing a minimum of hypertrophy work so what kind of weight have you gained? Mostly useless deconditioning body fat. "Bulking Up" is a bodybuilders game , but it only works to your benefit if you are focusing on hypertrophy.
Im not trying to down you at all, i just hate seeing someone who is dedicated waste there efforts with bad self defeating ideas. Worse , I hate seeing it get reinforced with strokes from others telling you how great it is. What will be great is when you hit good numbers.